Re: [PATCH v5 1/6] riscv: asm: alternative-macros: Introduce ALTERNATIVE_3() macro

Heiko Stuebner
2022-12-12T12:33:00Z

Am Montag, 12. Dezember 2022, 12:55:00 CET schrieb Prabhakar:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> Introduce ALTERNATIVE_3() macro.
>
> A vendor wants to replace an old_content, but another vendor has used
> ALTERNATIVE_2() to patch its customized content at the same location.
> In this case, this vendor can use macro ALTERNATIVE_3() and then replace
> ALTERNATIVE_2() with ALTERNATIVE_3() to append its customized content.
>
> While at it update comment above ALTERNATIVE_2() macro and make it generic
> so that the comment holds good for any new addition of ALTERNATIVE_X()
> macros.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>

> ---
> v4->v5
> * Rebased the patch on top of Andrew's series (now in Palmers for next-branch)
> * Updated comment for ALTERNATIVE_x() as suggested by Heiko
>
> RFC v3 -> v4
> * New patch
> ---
> arch/riscv/include/asm/alternative-macros.h | 46 ++++++++++++++++++---
> 1 file changed, 41 insertions(+), 5 deletions(-)
>
> diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h
> index 7226e2462584..a5b4691520da 100644
> --- a/arch/riscv/include/asm/alternative-macros.h
> +++ b/arch/riscv/include/asm/alternative-macros.h
> @@ -50,8 +50,17 @@
> ALT_NEW_CONTENT \vendor_id_2, \errata_id_2, \enable_2, \new_c_2
> .endm
>
> +.macro ALTERNATIVE_CFG_3 old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
> + new_c_2, vendor_id_2, errata_id_2, enable_2, \
> + new_c_3, vendor_id_3, errata_id_3, enable_3
> + ALTERNATIVE_CFG_2 \old_c, \new_c_1, \vendor_id_1, \errata_id_1, \enable_1, \
> + \new_c_2, \vendor_id_2, \errata_id_2, \enable_2
> + ALT_NEW_CONTENT \vendor_id_3, \errata_id_3, \enable_3, \new_c_3
> +.endm
> +
> #define __ALTERNATIVE_CFG(...) ALTERNATIVE_CFG __VA_ARGS__
> #define __ALTERNATIVE_CFG_2(...) ALTERNATIVE_CFG_2 __VA_ARGS__
> +#define __ALTERNATIVE_CFG_3(...) ALTERNATIVE_CFG_3 __VA_ARGS__
>
> #else /* !__ASSEMBLY__ */
>
> @@ -98,6 +107,13 @@
> __ALTERNATIVE_CFG(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1) \
> ALT_NEW_CONTENT(vendor_id_2, errata_id_2, enable_2, new_c_2)
>
> +#define __ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
> + new_c_2, vendor_id_2, errata_id_2, enable_2, \
> + new_c_3, vendor_id_3, errata_id_3, enable_3) \
> + __ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \
> + new_c_2, vendor_id_2, errata_id_2, enable_2) \
> + ALT_NEW_CONTENT(vendor_id_3, errata_id_3, enable_3, new_c_3)
> +
> #endif /* __ASSEMBLY__ */
>
> #define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, CONFIG_k) \
> @@ -108,6 +124,13 @@
> __ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, IS_ENABLED(CONFIG_k_1), \
> new_c_2, vendor_id_2, errata_id_2, IS_ENABLED(CONFIG_k_2))
>
> +#define _ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
> + new_c_2, vendor_id_2, errata_id_2, CONFIG_k_2, \
> + new_c_3, vendor_id_3, errata_id_3, CONFIG_k_3) \
> + __ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1, IS_ENABLED(CONFIG_k_1), \
> + new_c_2, vendor_id_2, errata_id_2, IS_ENABLED(CONFIG_k_2), \
> + new_c_3, vendor_id_3, errata_id_3, IS_ENABLED(CONFIG_k_3))
> +
> #else /* CONFIG_RISCV_ALTERNATIVE */
> #ifdef __ASSEMBLY__
>
> @@ -152,15 +175,28 @@
> _ALTERNATIVE_CFG(old_content, new_content, vendor_id, errata_id, CONFIG_k)
>
> /*
> - * A vendor wants to replace an old_content, but another vendor has used
> - * ALTERNATIVE() to patch its customized content at the same location. In
> - * this case, this vendor can create a new macro ALTERNATIVE_2() based
> - * on the following sample code and then replace ALTERNATIVE() with
> - * ALTERNATIVE_2() to append its customized content.
> + * ALTERNATIVE_x macros allow providing multiple replacement options
> + * for an ALTERNATIVE code section. This is helpful if multiple
> + * implementation variants for the same functionality exist for
> + * different cpu cores.
> + *
> + * Usage:
> + * ALTERNATIVE_x(old_content,
> + * new_content1, vendor_id1, errata_id1, CONFIG_k1,
> + * new_content2, vendor_id2, errata_id2, CONFIG_k2,
> + * ...
> + * new_contentx, vendor_idx, errata_idx, CONFIG_kx)
> */
> #define ALTERNATIVE_2(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
> new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2) \
> _ALTERNATIVE_CFG_2(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
> new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2)
>
> +#define ALTERNATIVE_3(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
> + new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2, \
> + new_content_3, vendor_id_3, errata_id_3, CONFIG_k_3) \
> + _ALTERNATIVE_CFG_3(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1, \
> + new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2, \
> + new_content_3, vendor_id_3, errata_id_3, CONFIG_k_3)
> +
> #endif